ABC News' Michael Falcone and Emily Friedman report:

SCOTTSDALE, Ariz. - Mitt Romney used a speech before an audience of some of the Republican National Committee's top leaders to put the Republican primary in the past.

Though his appearance here did not officially seal his ascent to the Republican presidential nomination - a path that is all but assured - he delivered an acceptance speech of sorts, publicly thanking the rivals from within his own party he was able to cast aside during the primary season as well as two who are still in the race.

"Let me also commend the people who had the courage to run for president on our side of the aisle this year. Some still running, some have gotten out of the race," Romney said. "And you know their names - it's a long enough list, I wrote it down, but Michele Bachmann, and Tim Pawlenty, and Jon Huntsman and Herman Cain, and Rick Perry, and Ron Paul and Rick Santorum and Newt Gingrich."

"Each is going to provide a vital role in making sure that we win in November," he added. "Thank you , this extraordinary team. We have all fought hard and well and we're going to fight for the things we believe in."

Noting that it was "good to see all his old friends," Romney spent the bulk of his speech repeating his critiques of President Obama and seizing on comments made by one of the president's advisors, David Axelrod, last week.

Axelrod, he said, "said something to the effect of we gotta get off the economic road we're on and take a new direction," said Romney. "I could not agree more. We have to make sure that we get off this road where more and more people are stuck into poverty, where it's tougher and tougher to be in the middle-class, where gasoline prices go higher and higher, where the unions are driving what's happening in our schools."

"This is a very difficult road we're on. It's time we're gonna get off it," he said.

"I'm convinced that the President was also right the other day when he said that we're gonna have two competing visions in the election in November. There's the vision which represents the road we're on, in David Axelrod's words, and there's a different vision, which is the vision which we represent," he said.

Romney, who addressed a three-day gathering of RNC state chairs and committeemen and women from around the country held at a resort here, dispatched a team of campaign aides to the event to help bring members who have not yet embraced his candidacy into the fold.

In his introduction of Romney, RNC Chairman Reince Priebus referred to him as a "businessman," "governor," "job creator," and "public servant," among other things. One word he did not use: "nominee."

But Priebus, who has steered the Republican Party out of a period of crushing debt, told Romney, "we want to welcome you in a formal way to a great family here."

Though Rick Santorum dropped out of the race last week, Gingrich and Paul are still competing in the primary, and it's mathematically impossible for Romney to officially clinch the nomination for weeks.

Sen. John McCain, R-Ariz., said in his own remarks at the party luncheon, that he was "most proud to have Mitt as our standard bearer."

But he added a warning too.

"Every day we are not campaigning and rounding up votes for Mitt Romney to be president is a day lost. So when we leave today, we are in the campaign, do not let an hour go by that we are not getting votes," McCain said. "This is going to be a very close election my folks. I believe that we are going to be up late on Election Night."